package LinkedList;

public class LeetCode_21_mergeTwoLists {
    public static class ListNode {
        int val;
        ListNode next;

        ListNode() {
        }

        ListNode(int val) {
            this.val = val;
        }

        ListNode(int val, ListNode next) {
            this.val = val;
            this.next = next;
        }
    }

    public static ListNode mergeTwoLists(ListNode list1, ListNode list2){
        if(list1 ==null) return list2;
        if(list2 ==null) return list1;
        if(list1.val <= list2.val){
            list1.next = mergeTwoLists(list1.next,list2);

            return list1;
        }else if(list2.val < list1.val){
            list2.next = mergeTwoLists(list1,list2.next);

            return list2;
        }
        return new ListNode();
    }

    public static void main(String[] args) {
        ListNode listNode = new ListNode(1);
        listNode.next = new ListNode(2);
        listNode.next.next = new ListNode(4);

        ListNode listNode2 = new ListNode(1);
        listNode2.next = new ListNode(3);
        listNode2.next.next = new ListNode(4);

        ListNode result = mergeTwoLists(listNode, listNode2);
        while (result != null){
            System.out.println(result.val);
            result = result.next;
        }
    }
}